U.S. patent application number 17/085913 was filed with the patent office on 2022-02-24 for wireless sensor device, host device, and method of controlling low-power operation of wireless sensor device.
This patent application is currently assigned to SEMES CO., LTD.. The applicant listed for this patent is SEMES CO., LTD.. Invention is credited to Dong Ok AHN, Yong Jun SEO, Sang Hyun SON.
Application Number | 20220060867 17/085913 |
Document ID | / |
Family ID | |
Filed Date | 2022-02-24 |
United States Patent
Application |
20220060867 |
Kind Code |
A1 |
SON; Sang Hyun ; et
al. |
February 24, 2022 |
WIRELESS SENSOR DEVICE, HOST DEVICE, AND METHOD OF CONTROLLING
LOW-POWER OPERATION OF WIRELESS SENSOR DEVICE
Abstract
A method of controlling a low-power operation of a wireless
sensor device includes performing a sensor-active step where the
wireless sensor device is active during the time taken for a
working mode in which the wireless sensor device performs multiple
tasks, and performing a sensor-inactive step where a mode of the
wireless sensor device is switched to a sleep mode after the
working mode is ended. The performing of the sensor-active step
includes receiving, after transmitting sensing data of a sensing
target to a host device that monitors and controls the wireless
sensor device, operation control information stored in the host
device from the host device.
Inventors: |
SON; Sang Hyun; (Busan,
KR) ; SEO; Yong Jun; (Hwaseong-si, KR) ; AHN;
Dong Ok; (Anyang-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEMES CO., LTD. |
Cheonan-si |
|
CN |
|
|
Assignee: |
SEMES CO., LTD.
Cheonan-si
KR
|
Appl. No.: |
17/085913 |
Filed: |
October 30, 2020 |
International
Class: |
H04W 4/38 20060101
H04W004/38; H04W 52/02 20060101 H04W052/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 31, 2019 |
KR |
10-2019-0137481 |
Claims
1. A method of controlling a low-power operation of a wireless
sensor device, the method comprising: performing a sensor-active
step where the wireless sensor device is active during the time
taken for a working mode in which the wireless sensor device
performs multiple tasks; and performing a sensor-inactive step
where a mode of the wireless sensor device is switched to a sleep
mode after the working mode is ended, wherein the performing of the
sensor-active step includes receiving, after transmitting sensing
data of a sensing target to a host device that monitors and
controls the wireless sensor device, operation control information
stored in the host device from the host device.
2. The method of claim 1, wherein the performing of the
sensor-active step includes causing the host device to recognize
switching to the working mode of the wireless sensor device on the
basis of transmission of the sensing data.
3. The method of claim 1, further comprising: repeatedly operating
the wireless sensor device in the working mode and the sleep
mode.
4. The method of claim 1, wherein the performing of the
sensor-active step comprises: sensing the sensing target;
transmitting the sensing data of the sensing target to the host
device; and receiving the stored operation control information from
the host device after the sensing data is transmitted to the host
device.
5. The method of claim 3, further comprising: setting a sensing
period for sensing the sensing target, wherein repeatedly operating
of the wireless sensor device in the working mode and the sleep
mode is performed in association with the sensing period.
6. The method of claim 4, wherein the receiving of the stored
operation control information includes receiving the operation
control information during a predetermined time limit that is set
considering data transmission characteristics of the host
device.
7. The method of claim 4, wherein the receiving of the stored
operation control information includes ending the working mode when
there is no data received from the host device during a threshold
time that is set for a waiting time for receiving data from the
host device.
8. A method of controlling a low-power operation of a wireless
sensor device, the method comprising: performing a control
information transmission step where a host device monitoring and
controlling the wireless sensor device transmits operation control
information stored in the host device to the wireless sensor device
as sensing data is received from the wireless sensor device; and
performing a control information storage step where the host device
stores operation control information for the wireless sensor device
as a mode of the wireless sensor device is switched to a sleep
mode.
9. The method of claim 8, wherein the performing of the control
information transmission step includes switching to a working mode
of the wireless sensor device being recognized on the basis of
transmission of the sensing data from the wireless sensor
device.
10. The method of claim 8, wherein the performing of the control
information transmission step and the performing of the control
information storage step are repeated by the host.
11. The method of claim 8, wherein the performing of the control
information storage step includes switching to the sleep mode being
recognized on the basis of a time limit for receiving information
that is set in association with transmission of the operation
control information according to data transmission characteristics
of the host device.
12. A wireless sensor device comprising: a sensing unit configured
to sense a sensing target; a sensor control unit configured to
repeatedly operate in between a working mode, in which multiple
tasks for transmitting sensing information of the sensing target to
a host device are processed, and a sleep mode, in which operation
of the wireless sensor device is stopped; and a sensor
communication unit configured to transmit and receive data from the
host device, wherein the sensor control unit is configured to
further receive, after sensing data of the sensing target is
transmitted to the host device, operation control information
stored in the host device from the host device and processes the
operation control information.
13. The wireless sensor device of claim 12, wherein the sensor
control unit is configured to cause the host device to recognize
switching to the working mode on the basis of transmission of the
sensing data of the sensing target.
14. The wireless sensor device of claim 12, wherein the sensor
control unit comprises: a mode setting unit configured to
repeatedly switch the mode between the working mode and the sleep
mode in association with a sensing period for sensing the sensing
target; and an operation control unit configured to receive the
stored operation control information from the host device, and
perform an operation according to the operation control
information.
15. The wireless sensor device of claim 14, wherein the mode
setting unit is configured to set a time limit for receiving
information considering data transmission characteristics of the
host device, and end the working mode on the basis of the time
limit for receiving information.
16. The wireless sensor device of claim 13, wherein the mode
setting unit is configured to set a threshold time for a waiting
time for receiving data from the host device, and end the working
mode when there is no data received from the host device during the
threshold time.
17. A host device monitoring and controlling a wireless sensor
device that repeatedly becomes active in association with a working
mode and inactive in association with a sleep mode, the host device
comprising: a control information storage unit configured to store
operation control information for the wireless sensor device; and a
control command unit configured to recognize switching to the
working mode of the wireless sensor device on the basis of
reception of sensing data from the wireless sensor device, and
transmit the stored operation control information to the wireless
sensor device.
18. The host device of claim 17, wherein the control command unit
is configured to recognize switching to the sleep mode of the
wireless sensor device on the basis of a time limit for receiving
information that is set considering data transmission
characteristics of the host device.
19. The host device of claim 17, further comprising: a sensor
monitoring unit configured to receive the sensing data from the
wireless sensor device, and monitor operation of the wireless
sensor device; a user interface configured to provide the sensing
data to a user, and receive a control command from the user; and a
host communication unit configured to transmit and receive data
from the wireless sensor device.
20. A method of controlling low-power operation of a wireless
sensor device, the method comprising: performing a first step where
the wireless sensor device is active during the time taken for a
working mode in which the wireless sensor device continuously
performs multiple tasks, and the wireless sensor device senses a
sensing target and transmits sensing data to a host device so that
the host device is made to recognize switching to the working mode
of the wireless sensor device; performing a second step where the
host device recognizes switching to the working mode of the
wireless sensor device as the sensing data is received from the
wireless sensor device, and the host device transmits, to the
wireless sensor device, operation control information stored during
the time taken for a sleep mode of the wireless sensor device;
performing a third step where the wireless sensor device receives
the operation control information and performs the tasks during a
time limit for receiving information that is set considering data
transmission characteristics of the host device; performing a
fourth step where the mode of the wireless sensor device is
switched to the sleep mode and the wireless sensor device becomes
inactive; and performing a fifth step where the host device stores
operation control information for the wireless sensor device as the
mode of the wireless sensor device is switched to the sleep mode,
wherein each of the steps is repeatedly performed depending on that
the wireless sensor device is active and inactive.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority to Korean Patent
Application No. 10-2019-0137481, filed Oct. 31, 2019, the entire
contents of which are herein incorporated by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present disclosure relates to a wireless sensor device,
a host device, and a method of controlling low-power operation of
the wireless sensor device. More particularly, the present
disclosure relates to a method that fulfills the following: in a
wireless sensor device operating between a working mode and a sleep
mode for low power operation, the time taken for the working mode
of the wireless sensor device is kept to a minimum, and when the
wireless sensor device transmits information on sensing data, a
host device transmits operation control information stored therein,
whereby the reception success rate of the operation control
information is maximized while the wireless sensor device operates
with low power.
Description of the Related Art
[0003] In various technical fields, such as factory automation
technology, crime prevention technology, home automation
technology, and the like, a physical quantity with respect to a
sensing target is measured through various types of sensors
depending on the form of each sensing target and types of sensing
data, and a result of measurement is used via a host device.
[0004] In the related art, a sensor system has been constructed
that connects various sensor devices to a host device in a wired
form of which physical implementation is simple. However, due to
various reasons, such as manufacture of the devices in a small and
slim size, the distance between the sensor device and the host
device, complexity of a wired configuration, and the like, the use
of a wireless sensor system that employs a wireless mobile sensor
device has increased rapidly.
[0005] In the case of the wireless mobile sensor device, the usage
capacity of the sensor device is limited because power is supplied
from an internal battery rather than an external power source due
to various constraints, such as installation convenience,
installation location, and the like. In order to manufacture the
sensor device in a small size, the capacity of the battery cannot
be greatly increased.
[0006] FIG. 1 is a diagram illustrating an embodiment of operation
of a conventional wireless sensor system.
[0007] The wireless sensor system may be schematically composed of
a host device 10 and wireless sensor devices 20a. The host device
10 monitors and controls the wireless sensor devices, and the
wireless sensor devices 20a are installed in a distributed manner
to measure a sensing target 30.
[0008] The wireless sensor system measures the physical quantity
with respect to the sensing target 30 at regular period intervals
and controls various situations on the basis of a result of the
measurement. The wireless sensor device 20a senses the sensing
target 30 at step S11 according to an n-th sensing period and then
transmits sensing data to the host device 10 at step S13. Then, the
host device 10 provides sensing information to a user or a
higher-level device managing the overall situation at step S15,
receives operation control information for the wireless sensor
device 20a accordingly at step S21, and gives a command to the
wireless sensor device 20a at step S22. According to the command of
the host device 10, the wireless sensor device 20a performs an
operation at step S23.
[0009] Herein, during an n-th sensing period, which is one sensing
period, multiple pieces of operation control information may be
input at steps S21, S24, and S27. Each time the operation control
information is input, the host device 10 gives a corresponding
command to the wireless sensor device 20a at steps S22, S25, and
S28. The wireless sensor device 20a performs an operation according
to each command at steps S23, S26, S29.
[0010] In addition, the above-described process is repeatedly
performed during an n+1-th sensing period, which is the subsequent
sensing period. The operation shown in FIG. 1 enables a user's
commands to be immediately carried out, but accordingly, the
wireless sensor device 20a needs to be kept in an active state at
all times. Therefore, the power consumption of the wireless sensor
device 20a is considerably large so that it is necessary to
frequently charge or replace the battery.
[0011] In order to solve such a problem, a method has been proposed
in which a wireless sensor device operates switching between an
active state and an inactive state and a duty cycle, which is the
degree of maintenance of the active state, is adjusted during a
sensing period.
[0012] FIG. 2 is a diagram illustrating an embodiment of an
operation of adjusting a duty cycle of a wireless sensor system in
the related art.
[0013] As shown in FIG. 2, while a wireless sensor device 20b
operates in an working mode at step S50, the wireless sensor device
20b enters an active state 21a, performs sensing on a sensing
target 30 at step S51, and transmits sensing data at step S53, and
so on. In addition, the wireless sensor device 20b receives, from
the host device 10, a command (S61) based on operation control
information at step S62 and performs an operation accordingly at
step S63.
[0014] When the mode of the wireless sensor device 20b is switched
to a sleep mode at step S70 and thus enters an inactive state 25a,
operation control information (S64, S67) is not received from the
host device 10 any longer, so that the operation control
information is lost at steps S65 and S68). Even though the
operation control information is lost, the host device 10
erroneously recognizes that the operation control information is
transmitted. This is an error.
[0015] In order to increase the reception success rate by reducing
the loss of operation control information and operate the wireless
sensor device with low power, a method has been proposed in which
the host device transmits a wake-up signal, which commands
switching from the sleep mode to the working mode, to the wireless
sensor device.
[0016] However, due to the characteristics of wireless
communication, considerable power is consumed for the operation of
a wireless communication module. In order to receive the wake-up
signal, the wireless communication module of the wireless sensor
device needs to wait the wake-up signal in the working state so
that the wake-up signal unexpectedly transmitted is recognized.
This is also a problem that is inappropriate for driving the
wireless sensor device with low power.
[0017] The foregoing is intended merely to aid in the understanding
of the background of the present disclosure, and is not intended to
mean that the present disclosure falls within the purview of the
related art that is already known to those skilled in the art.
SUMMARY OF THE INVENTION
[0018] The present disclosure is directed to providing a method of
optimally operating a wireless sensor device with low power
according to the limit of battery capacity caused by manufacture of
the wireless sensor device in a small and slim size.
[0019] Further, when the mode of the wireless sensor device is
switched to the sleep mode so as to operate the wireless sensor
device with low power, operation control information is not
received from a host device any longer, so that there is a problem
that the operation control information is lost. There is another
problem that despite the loss of the operation control information,
the host device erroneously recognizes that the operation control
information is transmitted. The present disclosure is intended to
solve these problems.
[0020] Further, in the case of a method in which the host device
transmits, to the wireless sensor device, a wake-up signal that
commands switching from the sleep mode to the working mode, a
wireless communication module of the wireless sensor device waits
being always in a working state in order to receive the wake-up
signal, resulting a problem that the power of the wireless sensor
device is consumed. The present disclosure is intended to solve
this problem.
[0021] According to an exemplary embodiment of the present
invention, a method of controlling a low-power operation of a
wireless sensor device includes performing a sensor-active step
where the wireless sensor device is active during the time taken
for a working mode in which the wireless sensor device performs
multiple tasks, and performing a sensor-inactive step where a mode
of the wireless sensor device is switched to a sleep mode after the
working mode is ended. The performing of the sensor-active step
includes receiving, after transmitting sensing data of a sensing
target to a host device that monitors and controls the wireless
sensor device, operation control information stored in the host
device from the host device.
[0022] The performing of the sensor-active step includes causing
the host device to recognize switching to the working mode of the
wireless sensor device on the basis of transmission of the sensing
data.
[0023] The method of controlling the low-power operation of the
wireless sensor device further includes repeatedly operating the
wireless sensor device in the working mode and the sleep mode.
[0024] The performing of the sensor-active step includes sensing
the sensing target, transmitting the sensing data of the sensing
target to the host device, and receiving the stored operation
control information from the host device after the sensing data is
transmitted to the host device.
[0025] The method of controlling the low-power operation of the
wireless sensor device further includes setting a sensing period
for sensing the sensing target. Repeatedly operating of the
wireless sensor device in the working mode and the sleep mode is
performed in association with the sensing period.
[0026] The receiving of the stored operation control information
includes receiving the operation control information during a
predetermined time limit that is set considering data transmission
characteristics of the host device.
[0027] The receiving of the stored operation control information
includes ending the working mode when there is no data received
from the host device during a threshold time that is set for a
waiting time for receiving data from the host device.
[0028] According to an exemplary embodiment of the present
invention, a method of controlling a low-power operation of a
wireless sensor device includes performing a control information
transmission step where a host device monitoring and controlling
the wireless sensor device transmits operation control information
stored in the host device to the wireless sensor device as sensing
data is received from the wireless sensor device, and performing a
control information storage step where the host device stores
operation control information for the wireless sensor device as a
mode of the wireless sensor device is switched to a sleep mode.
[0029] The performing of the control information transmission step
includes switching to a working mode of the wireless sensor device
being recognized on the basis of transmission of the sensing data
from the wireless sensor device.
[0030] The performing of the control information transmission step
and the performing of the control information storage step are
repeated by the host.
[0031] The performing of the control information storage step
includes switching to the sleep mode being recognized on the basis
of a time limit for receiving information that is set in
association with transmission of the operation control information
according to data transmission characteristics of the host
device.
[0032] According to an exemplary embodiment of the present
invention, a wireless sensor device includes a sensing unit
configured to sense a sensing target, a sensor control unit
configured to repeatedly operate in between a working mode, in
which multiple tasks for transmitting sensing information of the
sensing target to a host device are processed, and a sleep mode, in
which operation of the wireless sensor device is stopped, and a
sensor communication unit configured to transmit and receive data
from the host device. The sensor control unit is configured to
further receive, after sensing data of the sensing target is
transmitted to the host device, operation control information
stored in the host device from the host device and processes the
operation control information.
[0033] The sensor control unit is configured to cause the host
device to recognize switching to the working mode on the basis of
transmission of the sensing data of the sensing target.
[0034] The sensor control unit includes a mode setting unit
configured to repeatedly switch the mode between the working mode
and the sleep mode in association with a sensing period for sensing
the sensing target, and an operation control unit configured to
receive the stored operation control information from the host
device, and perform an operation according to the operation control
information.
[0035] The mode setting unit is configured to set a time limit for
receiving information considering data transmission characteristics
of the host device, and end the working mode on the basis of the
time limit for receiving information.
[0036] The mode setting unit is configured to set a threshold time
for a waiting time for receiving data from the host device, and end
the working mode when there is no data received from the host
device during the threshold time.
[0037] According to an exemplary embodiment of the present
invention, a host device monitoring and controlling a wireless
sensor device that repeatedly becomes active in association with a
working mode and inactive in association with a sleep mode includes
a control information storage unit configured to store operation
control information for the wireless sensor device, and a control
command unit configured to recognize switching to the working mode
of the wireless sensor device on the basis of reception of sensing
data from the wireless sensor device, and transmit the stored
operation control information to the wireless sensor device.
[0038] The control command unit is configured to recognize
switching to the sleep mode of the wireless sensor device on the
basis of a time limit for receiving information that is set
considering data transmission characteristics of the host
device.
[0039] The host device further includes a sensor monitoring unit
configured to receive the sensing data from the wireless sensor
device, and monitor operation of the wireless sensor device, a user
interface configured to provide the sensing data to a user, and
receive a control command from the user, and a host communication
unit configured to transmit and receive data from the wireless
sensor device.
[0040] According to an exemplary embodiment of the present
invention, a method of controlling low-power operation of a
wireless sensor device includes performing a first step where the
wireless sensor device is active during the time taken for a
working mode in which the wireless sensor device continuously
performs multiple tasks, and the wireless sensor device senses a
sensing target and transmits sensing data to a host device so that
the host device is made to recognize switching to the working mode
of the wireless sensor device, performing a second step where the
host device recognizes switching to the working mode of the
wireless sensor device as the sensing data is received from the
wireless sensor device, and the host device transmits, to the
wireless sensor device, operation control information stored during
the time taken for a sleep mode of the wireless sensor device,
performing a third step where the wireless sensor device receives
the operation control information and performs the tasks during a
time limit for receiving information that is set considering data
transmission characteristics of the host device, performing a
fourth step where the mode of the wireless sensor device is
switched to the sleep mode and the wireless sensor device becomes
inactive, and performing a fifth step where the host device stores
operation control information for the wireless sensor device as the
mode of the wireless sensor device is switched to the sleep mode.
Each of the steps is repeatedly performed depending on that the
wireless sensor device is active and inactive.
[0041] According to the present disclosure, while the battery
capacity is minimized for manufacture of the wireless sensor device
in a small and slim size, the wireless sensor device operates with
low power in a manner that greatly increases the reception success
rate of the operation control information from the host device.
[0042] Further, it is possible to prevent an error operation that
occurs due to loss of operation control information caused by
adjustment of a duty cycle for low-power operation.
[0043] In particular, in the wireless sensor device operating
between the working mode and the sleep mode for low-power
operation, the time taken for the working mode of the wireless
sensor device is kept to a minimum, so that power consumption is
minimized. In addition, when the wireless sensor device transmits
information on sensing data, the host device transmits operation
control information stored therein to the wireless sensor device.
Therefore, while the wireless sensor device operates with minimum
power, the reception success rate of the operation control
information is maximized. Accordingly, the wireless sensor system
efficiently operates.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] The above and other objectives, features, and other
advantages of the present disclosure will be more clearly
understood from the following detailed description when taken in
conjunction with the accompanying drawings, in which:
[0045] FIG. 1 is a diagram illustrating an embodiment of operation
of a general wireless sensor system in the related art;
[0046] FIG. 2 is a diagram illustrating an embodiment of an
operation of adjusting a duty cycle of a wireless sensor system in
the related art;
[0047] FIG. 3 is a diagram illustrating an embodiment of a wireless
sensor system according to the present disclosure;
[0048] FIG. 4 is a conceptual diagram illustrating operation of a
wireless sensor system according to the present disclosure;
[0049] FIGS. 5A and 5B are diagrams illustrating a configuration of
an embodiment of a wireless sensor device according to the present
disclosure;
[0050] FIG. 6 is a diagram illustrating a configuration of an
embodiment of a host device according to the present
disclosure;
[0051] FIG. 7 is a flowchart illustrating an embodiment of a method
of controlling low-power operation of a wireless sensor device
according to the present disclosure; and
[0052] FIG. 8 is a flowchart illustrating an embodiment in which
the time taken for a working mode of a wireless sensor device is
adjusted, in the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0053] In order to describe the present disclosure, operational
advantages of the present disclosure, and the objectives achieved
by embodying the present disclosure, exemplary embodiments of the
present disclosure will be described hereinbelow.
[0054] First, the terms used in the present application are merely
used to describe particular embodiments, and are not intended to
limit the present disclosure. Further, the singular forms "a",
"an", and "the" are intended to include the plural forms as well,
unless the context clearly indicates otherwise. In addition, in the
present application, it is to be understood that terms such as
"including", "having", etc. are intended to indicate the existence
of the features, numbers, steps, actions, elements, parts, or
combinations thereof disclosed in the specification, and are not
intended to preclude the possibility that one or more other
features, numbers, steps, actions, elements, parts, or combinations
thereof may exist or may be added.
[0055] In describing the present disclosure, if it is decided that
the detailed description of known function or configuration related
to the disclosure makes the subject matter of the disclosure
unclear, the detailed description is omitted.
[0056] The present disclosure provides a method that fulfills the
following: in a wireless sensor device operating between a working
mode and a sleep mode for low power operation, the time taken for
the working mode of the wireless sensor device is kept minimum, and
when the wireless sensor device transmits information on sensing
data, a host device transmits operation control information stored
therein, whereby the reception success rate of the operation
control information is maximized while the wireless sensor device
operates with low power.
[0057] FIG. 3 is a diagram illustrating an embodiment of a wireless
sensor system according to the present disclosure.
[0058] According to the present disclosure, the wireless sensor
system includes a host device 100 and a wireless sensor device 200.
The wireless sensor device 200 measures the physical quantity with
respect to a sensing target according to various sensing conditions
of the sensing target, such as a form, a location, the degree of
change, and the like. The host device 100 controls the wireless
sensor device by monitoring the same.
[0059] In the present disclosure, the types and the forms of the
wireless sensor devices 200 may vary according to the sensing
target. Therefore, the wireless sensor device 200 is not limited to
a particular wireless sensor device. Depending on the sensing
function, installation location, the physical quantity with respect
to the measurement target, and the like, various wireless sensor
devices 200a, 200b, . . . , 200n may be applied. Fundamentally, the
wireless sensor device 200 refers to a wireless sensor device 200
that performs data communication with the host device 100 by using
a wireless communication method.
[0060] Herein, as the wireless communication between the host
device and the wireless sensor device, a communication method, such
as Zigbee, Bluetooth, Wi-Fi, WiBro, or the like, suitable for the
situation may be applied according to the characteristics of
transmission data, a wireless communication environment, or the
like. The wireless sensor device 200 has a function of being active
through operation in a working mode or being inactive through
operation in a sleep mode, and operates according to each mode
switching.
[0061] The host device 100 receives, from the wireless sensor
device 200, sensing data sensed from the sensing target. The host
device 100 provides the sensing data to a user, or provides the
sensing data to a higher-level device that requires the sensing
data. Subsequently, the host device 100 transmits operation control
information for controlling the wireless sensor device 200 to the
wireless sensor device 200, thereby managing and controlling the
wireless sensor device 200.
[0062] The number of the wireless sensor devices 200 that the host
device 100 manages and controls may vary between situation
conditions.
[0063] The fundamental concept of the present disclosure applied to
such a wireless sensor system will be described with reference to
FIG. 4.
[0064] In FIG. 4, an operation between one wireless sensor device
200 and the host device 100 is described for convenience of
description, and the number of the wireless sensor devices 200 may
vary when necessary. In addition, in FIG. 4, the concept of
operations in an active state and an inactive state according to a
sensing period that is preset considering the characteristics of
the device is described, but is not limited thereto. When
necessary, rather than regular sensing periods, operations in an
irregular active state and an irregular inactive state according to
the user's setting or control by the higher-level device may be
implemented.
[0065] FIG. 4 shows a fundamental operation of the wireless sensor
device 200 for each sensing period and a corresponding operation of
the host device 100.
[0066] In an n-1-th sensing period, the wireless sensor device 200
becomes active, performs an operation, and becomes inactive due to
switching to the sleep mode, and thus the wireless sensor device
200 stops all operations. Herein, all components other than the
components for mode switching stop operating because power supply
is cut off. That is, power supply to all components including a
communication module except essential components, such as a timer,
and the like, for determining the sensing period of the wireless
sensor device 200 is cut off so that power consumption is
minimized.
[0067] When the mode of the wireless sensor device 200 is switched
to the sleep mode and the wireless sensor device 200 becomes
inactive, the host device 100 recognizes switching to the sleep
mode of the wireless sensor device 200. Herein, switching to the
sleep mode of the wireless sensor device 200 is recognized by
receiving information on switching to the sleep mode from the
wireless sensor device 200, or recognized as the corresponding time
has elapsed measured by a timer that the host device 100 has. The
timer is to determine the sensing period and is synchronized with
the timer of the wireless sensor device 200.
[0068] When switching to the sleep mode of the wireless sensor
device 200 is recognized, the host device 100 does not maintain
communication with the wireless sensor device 200 any longer and
operates independently. As the independent operation, when the host
device 100 receives operation control information for the wireless
sensor device 200 from the user or the higher-level device, the
host device 100 stores the operation control information.
[0069] As an n-th sensing period begins and the mode of the
wireless sensor device 200 is switched to the working mode, the
wireless sensor device 200 performs corresponding tasks, such as
sensing the sensing target, transmitting sensing data, forming a
wireless communication line with the host device, and the like.
[0070] Herein, the time taken to maintain the working mode as the
wireless sensor device 200 becomes active may be set considering
the tasks to be performed, the characteristics of wireless
communication with the host device 100, and the like. As the time
taken to maintain the working mode has elapsed, the wireless sensor
device 200 ends the working mode and the mode is switched to the
sleep mode.
[0071] The host device 100 may recognize switching to the working
mode of the wireless sensor device 200 by receiving a signal
indicating switching to the working mode from the wireless sensor
device 200. However, preferably, operating in the working mode is
recognized by information on sensing data transmitted from the
wireless sensor device 200.
[0072] When the host device 100 receives the information on the
sensing data from the wireless sensor device 200, the host device
100 extracts the stored operation control information and transmits
the operation control information to the wireless sensor device
200. As the operation control information is transmitted from the
host device 100, the wireless sensor device 200 performs a task of
the corresponding operation.
[0073] When the mode of the wireless sensor device 200 is switched
to the sleep mode, the host device 100 recognizes switching and
stores operation control information for the wireless sensor device
200 as an independent operation.
[0074] As described above, in the present disclosure, the wireless
sensor device repeatedly becomes active and inactive every sensing
period. Correspondingly, the host device performs a task
corresponding to the active state of the wireless sensor device and
an independent task corresponding to the inactive state.
[0075] Herein, in order to reduce power usage as much as possible,
the wireless sensor device stops supplying power to all components
except the essential components for determining the sensing period
during the sleep mode. The host device stores the operation control
information during the sleep mode of the wireless sensor device in
order to prevent the operation control information from being lost
due to a failure of transmission of the operation control
information caused by interruption to communication with the
wireless sensor device. When the mode of the wireless sensor device
is switched to the working mode, the stored operation control
information is transmitted.
[0076] Hereinafter, the wireless sensor device and the host device
of the wireless sensor system according to the present disclosure
will be described in detail with reference to an embodiment.
[0077] FIGS. 5A and 5B are diagrams illustrating a configuration of
an embodiment of a wireless sensor device according to the present
disclosure.
[0078] Regarding the embodiment of the wireless sensor device 200
according to the present disclosure shown in FIG. 5A, the wireless
sensor device 200 may include a sensing unit 210, a sensor control
unit 230, a sensor communication unit 250, and the like. When
necessary, the wireless sensor device 200 may further include
additional components that may be included in known wireless sensor
devices. However, a description of the components other than the
gist of the present disclosure will be omitted.
[0079] The sensing unit 210 senses the sensing target and generates
sensing data. A sensor included in the sensing unit 210 may be
variously modified according to the sensing target, the physical
quantity to be measured, or the like.
[0080] *68 The sensor control unit 230 manages and control each
component of the wireless sensor device 200. In the present
disclosure, the sensor control unit 230 has a function of
repeatedly performing switching between the working mode, in which
multiple tasks for transmitting the sensing information of the
sensing target to the host device are processed, and the sleep
mode, in which the operation of the wireless sensor device is
stopped. Preferably, the sensing period for sensing the sensing
target is set, and mode switching is repeatedly performed in
association with the sensing period.
[0081] The sensor communication unit 250 transmits and receives
data from the host device 100 through wireless communication.
Herein, various wireless communication methods, such as Zigbee,
Bluetooth, Wi-Fi, WiBro, and the like, may be applied considering
the characteristics of the host device 100 and the wireless sensor
device 200, an installation environment, and the like.
[0082] Regarding the sensor control unit 230 in detail, which is
the main feature of the wireless sensor device 200 according to the
present disclosure, the sensor control unit 230 may receive the
stored operation control information from the host device 100
during the working mode and may process the task corresponding to
the operation control information. The sensor control unit 230 may
further include detailed components as shown in FIG. 5B.
[0083] A mode setting unit 231 may repeatedly switch the mode of
the wireless sensor device 200 between the working mode and the
sleep mode in association with the sensing period. An operation
control unit 235 receives the stored operation control information
from the host device 100 as the mode setting unit 231 switches the
mode to the working mode. As the operation control information is
received, the operation control unit 235 performs a task
corresponding to the operation control information.
[0084] Preferably, as the mode is switched to the working mode, the
operation control unit 235 transmits information on sensing data to
the host device 100. As the information on sensing data is
transmitted, the stored operation control information is received
from the host device 100.
[0085] More preferably, starting from transmission of the sensing
data, the stored operation control information is received from the
host device 100. During any other time period, the operation
control information is not received from the host device 100.
[0086] The task performed by the operation control unit 235
according to the operation control information may include various
tasks, such as setting the sensing period, setting and adjusting
sensing sensitivity and wireless communication, synchronization of
the timer determining the sensing period, and the like.
[0087] Preferably, the mode setting unit 231 sets the time limit
for receiving information considering the data transmission
characteristics of the host device 100, such as a communication
method, a packet format, data transmission rate, and the like. When
the time limit for receiving information has elapsed in the middle
of the working mode, the mode setting unit 231 ends the working
mode. To this end, the mode setting unit 231 may include a timer
that determines whether the time limit for receiving information
has elapsed. The timer of the mode setting unit 231 is synchronized
with the timer of the host device 100, so the host device 100
recognizes that the mode of the wireless sensor device 200 is
switched to the sleep mode due to the end of the working mode
caused by the end of the time limit for receiving information.
[0088] Further, the mode setting unit 231 may set a threshold time
for the waiting time for receiving data from the host device 100.
When there is no data received from the host device 100 during the
threshold time, the mode setting unit 231 ends the working mode and
switches the mode to the sleep mode. Accordingly, it is possible to
prevent unnecessary power consumption that is caused by maintaining
communication even when there is no data transmitted from the host
device 100.
[0089] FIG. 6 is a diagram illustrating a configuration of an
embodiment of a host device according to the present
disclosure.
[0090] In the present disclosure, the host device 100 is a device
that is capable of monitoring and controlling the wireless sensor
device 200 that repeatedly becomes active in the working mode and
inactive as the mode is switched to the sleep mode.
[0091] The host device 100 schematically may include a sensor
monitoring unit 110, a control command unit 130, a control
information storage unit 150, a user interface 170, a host
communication unit 190, and the like. In addition, additional
components capable of remotely monitoring and controlling the
multiple wireless sensor devices 200 may be included, but a
description of components other than the characteristic components
of the present disclosure will be omitted.
[0092] The sensor monitoring unit 110 has a function of receiving
the sensing data from the wireless sensor device 200 and monitoring
the operation of the wireless sensor device 200. Depending on the
situation, being in in conjunction with the higher-level device,
the sensor monitoring unit 110 may convert the sensing data of the
wireless sensor device 200 into data in an appropriate format and
provide the resulting data to the higher-level device, and may
receive operation control information corresponding thereto.
[0093] Being in conjunction with the sensor monitoring unit 110,
the user interface 170 may provide the sensing data of the wireless
sensor device 200 to the user and may receive operation control
information for the wireless sensor device 200 from the user.
Herein, the user interface 170 may function as an interface that is
connected with the user's terminal.
[0094] In addition, the control information storage unit 150
generates and stores operation control information for the wireless
sensor device 200. Herein, the operation control information may be
information that is generated by being received from the user
through the user interface 170 or from the higher-level device. In
particular, the control information storage unit 150 stores the
operation control information during the sleep mode of the wireless
sensor device 200.
[0095] The control command unit 130 recognizes the switching of the
mode of the wireless sensor device 200 between the working mode and
the sleep mode. As the mode is switched to the sleep mode, the
control command unit 130 supports the control information storage
unit 150 to store the operation control information. As the mode is
switched to the working mode, the control command unit 130
transmits the operation control information stored in the control
information storage unit 150 to the wireless sensor device 200.
[0096] Herein, regarding the recognition of switching to the
working mode, the control command unit 130 may recognize switching
by receiving information on switching to the working mode from the
wireless sensor device 200. Preferably, the control command unit
130 recognizes transmission of the sensing data from the wireless
sensor device 200, thereby recognizing switching to the working
mode. In addition, regarding the recognition of switching to the
sleep mode, the control command unit 130 may recognize switching by
receiving information on switching to the sleep mode from the
wireless sensor device 200. Preferably, the control command unit
130 recognizes the time limit for receiving information, which is
set in association with the end of the working mode, through the
timer, or the like, thereby recognizing switching to the sleep
mode.
[0097] In addition, the control information storage unit 150
stores, on the basis of the recognition of switching to the sleep
mode by the control command unit 130, the operation control
information during the sleep mode of the wireless sensor device
200. When the mode is switched to the working mode according to the
subsequent sensing period of the wireless sensor device 200, the
control command unit 130 extracts the operation control information
stored in the control information storage unit 150 and transmits
the operation control information to the wireless sensor device
200.
[0098] In the present disclosure, through the wireless sensor
system composed of the host device 100 and the wireless sensor
device 200 described above, the power of the wireless sensor device
is used with maximum efficiency, and the operation control
information from the host device 100 is prevented from being lost,
thereby planning stable operation of the entire system.
Hereinafter, a method of controlling low-power operation of a
wireless sensor device through the wireless sensor system according
to the present disclosure will be described.
[0099] The method of controlling low-power operation of the
wireless sensor device through the wireless sensor system according
to the present disclosure may be divided, on the basis of a
performer that performs each process, into a method of controlling
low-power operation according to the operation of the wireless
sensor device 200 and a method of controlling low-power operation
according to the operation of the host device 100.
[0100] First, the method of controlling low-power operation
according to the operation of the wireless sensor device 200
schematically includes: a sensor-active step where the wireless
sensor device 200 is active during the time taken for the working
mode in which the wireless sensor device 200 continuously performs
multiple tasks; and a sensor-inactive step where the mode of the
wireless sensor device 200 is switched to the sleep mode as the
working mode is ended. The wireless sensor device 200 repeatedly
performs the sensor-active step and the sensor-inactive step.
[0101] Herein, during the sensor-active step, as the wireless
sensor device 200 transmits sensing data of the sensing target to
the host device 100, the wireless sensor device 200 receives the
stored operation control information from the host device 100.
[0102] In addition, regarding the method of controlling low-power
operation according to the operation of the host device 100, a
description of the basic operation that the host device 100
monitors and manages the wireless sensor device 200 will be omitted
and the features of the present disclosure will be schematically
described. The method includes: a control information transmission
step where as the host device 100 receives the sensing data from
the wireless sensor device 200, the host device 100 transmits the
stored operation control information to the wireless sensor device
200; and a control information storage step where, as the mode of
the wireless sensor device 200 is switched to the sleep mode, the
host device 100 stored operation control information for the
wireless sensor device 200. The host device 100 repeatedly performs
the control information transmission step and the control
information storage step.
[0103] As described above, in the method of controlling low-power
operation of the wireless sensor device according to the present
disclosure, the wireless sensor device repeatedly becomes active in
association with the working mode and inactive in association with
the sleep mode, thereby minimizing power usage in the sleep mode.
Herein, during the sleep mode of the wireless sensor device, the
host device stores the operation control information. When the mode
is switched to the working mode, the host device transmits the
stored operation control information to the wireless sensor
device.
[0104] Hereinafter, the method of controlling low-power operation
of the wireless sensor device according to the present disclosure
will be described in more detail. The method of controlling
low-power operation of the wireless sensor device according to the
present disclosure is implemented according to the interworking
operation between the host device 100 and the wireless sensor
device 200. Synthesizing the operations of the host device 100 and
the wireless sensor device 200, an embodiment of the method of
controlling low-power operation of the wireless sensor device
according to the present disclosure will be described with
reference to FIG. 7.
[0105] In the embodiment shown in FIG. 7, the wireless sensor
device 200 sets the sensing period in which the sensing target 300
is sensed, and the wireless sensor device 200 repeatedly becomes
active and inactive in association with the sensing period.
[0106] As an n-th sensing period begins, the wireless sensor device
200 switches the mode to the working mode at step S110, becomes
active (210a), and performs a task accordingly. The wireless sensor
device 200 performs n-th sensing on the sensing target 300 at step
S111 and transmits sensing data to the host device 100 at step
S113.
[0107] As the sensing data is transmitted from the wireless sensor
device 200, the host device 100 provides the sensing data to the
user or the higher-level device at step S119.
[0108] As the sensing data is transmitted, the wireless sensor
device 200 receives the stored operation control information from
the host device 100. When the operation control information is not
transmitted, the wireless sensor device 200 ends the working mode,
switches the mode to the sleep mode at step S120, and thus enters
an inactive state (250a). As the mode is switched to the sleep
mode, power supply to power components other than the essential
components for determining the sensing period is cut off to stop
operation.
[0109] The host device 100 recognizes switching to the sleep mode
of the wireless sensor device 200 and does not maintain
communication any longer while the wireless sensor device 200 is in
the inactive state. During the sleep mode, when operation control
is input from the user or the higher-level device, the host device
100 generates operation control information C.sub.n1) at step S121
and stores the generated operation control information C.sub.n(1)
at step S123. As shown in FIG. 7, operation control may be input
multiple times from the user or the higher-level device.
Correspondingly, the host device 100 generates operation control
information C.sub.n(N) at step S125 for the additionally input
operation control, and stores the resulting information at step
S127.
[0110] That is, in a state where communication is lost due to
switching to the sleep mode of the wireless sensor device 200, the
host device 100 stores the operation control information for the
wireless sensor device 200 until the subsequent switching to the
working mode.
[0111] As an n+1-th sensing period begins, the wireless sensor
device 200 switches the mode to the working mode at step S130,
enters an active state, and performs a task accordingly. As
described above, the wireless sensor device 200 performs n+1-th
sensing on the sensing target 300 at step S131 and transmits
corresponding sensing data to the host device 100 at step S133.
[0112] The host device 100 recognizes switching to the working mode
of the wireless sensor device 200. Herein, transmission of n+1-th
sensing data is recognized, whereby switching to the working mode
is recognized. As the sensing data is transmitted from the wireless
sensor device 200, the host device 100 extracts the stored
operation control information C.sub.n and transmits the resulting
information to the wireless sensor device 200 at step S136. The
wireless sensor device 200 performs an operation at step S137 in
association with the operation control information transmitted from
the host device 100.
[0113] When the wireless sensor device 200 switches the mode back
to the sleep mode at step S140 and enters an inactive state (250b),
the host device 100 recognizes switching to the sleep mode of the
wireless sensor device 200, does not maintain communication any
longer, and performs an independent task. As the independent task,
the host device 100 generates and stores operation control
information C.sub.n+1, and waits until the wireless sensor device
200 switches the mode to the working mode as an n+2-th sensing
period begins.
[0114] Further, for more efficient operation, the time taken to
maintain the active state during the working mode of the wireless
sensor device may be set. FIG. 8 is a flowchart illustrating an
embodiment in which the time taken for a working mode of a wireless
sensor device is adjusted, in the present disclosure.
[0115] As the mode is switched to the working mode at step S210,
when the wireless sensor device 200 enters an active state, the
wireless sensor device 200 identifies whether the operation control
information is received from the host device 100 at step S220 while
performing multiple preset tasks in the working mode.
[0116] In the wireless sensor device 200, a threshold time for the
waiting time for receiving data from the host device 100 is set.
Herein, the threshold time may be appropriately set by the user or
the like, considering the data transmission characteristics of the
host device.
[0117] When there is no data received from the host device 100
during the threshold time, the wireless sensor device 200
determines whether the threshold time is exceeded at step S230.
When the threshold time is exceeded, the wireless sensor device 200
ends the working mode and switches the mode to the sleep mode at
step S260.
[0118] In addition, the time limit for receiving operation control
information from the host device 100 may be set in the wireless
sensor device 200. Herein, the time limit for receiving information
may be set considering the characteristics of data transmission
with the host device 100.
[0119] For example, the time limit for receiving information may be
set considering various factors, such as what type the wireless
communication method is, what type the data packet is, what the
rate of communication between the host device and the wireless
sensor device is, and so on. Further, a predetermined additional
time may be considered for stability of data reception. The time
limit for receiving information may be automatically set
considering various conditions or may be set by the user.
[0120] When the wireless sensor device 200 receives the operation
control information from the host device 100 at step S220, while
performing a task corresponding to the operation control
information at step S240, the wireless sensor device 200 determines
whether the time limit for receiving information is exceeded at
step S250. When the time limit for receiving information is not
exceeded, receiving of the operation control information keeps
performing. However, when the time limit for receiving information
is exceeded, the wireless sensor device 200 ends the working mode,
switches the mode to the sleep mode at step S260, and enters the
inactive state.
[0121] As described, when the time limit for receiving information
is exceeded, the data transmitted from the host device may be lost.
Therefore, the wireless sensor device 200 may transmit information
on exceeding the time limit for receiving information to the host
device 100. Alternatively, the wireless sensor device 200 may share
the time limit for receiving information set in the wireless sensor
device 200 with the host device 100 and the host device 100
recognizes that the time limit for receiving information is
exceeded through synchronization of the timers installed on the
host device 100 and the wireless sensor device 200,
respectively.
[0122] Further, the method of controlling low-power operation of
the wireless sensor device according to the present disclosure may
be implemented by performing each step through the operation of a
computer program. To this end, according to the present disclosure,
the wireless sensor device or the host device may include a storage
medium on which the computer program performing the steps proposed
in the method of controlling low-power operation of the wireless
sensor device is stored, and a computing element included in the
wireless sensor device or the host device loads and drives the
computer program stored on the storage medium, thereby implementing
the present disclosure. Preferably, the wireless sensor device or
the host device is equipped with firmware that operates by driving
the computer program. The steps proposed in the method of
controlling low-power operation of the wireless sensor device may
be performed through the firmware, thereby implementing the present
disclosure.
[0123] According to the present disclosure, while the battery
capacity is minimized for manufacture of the wireless sensor device
in a small and slim size, the wireless sensor device operates with
low power in a manner that greatly increases the reception success
rate of the operation control information from the host device.
[0124] In particular, in the wireless sensor device operating
between the working mode and the sleep mode for low-power
operation, the time taken for the working mode of the wireless
sensor device is kept to a minimum, so that power consumption is
minimized. In addition, the host device stores operation control
information during the time taken for the sleep mode of the
wireless sensor device, and when the mode of the wireless sensor
device is switched to the working mode, the host device transmits
the stored operation control information to the wireless sensor
device. Therefore, while the wireless sensor device operates with
minimum power, the reception success rate of the operation control
information is maximized. Accordingly, the wireless sensor system
efficiently operates.
[0125] The above description is merely intended to exemplarily
describe the technical idea of the present disclosure, and those
skilled in the art will appreciate that various changes and
modifications are possible without departing from the essential
features of the present disclosure. Therefore, the embodiments
disclosed in the present disclosure are not intended to restrict
the technical idea of the present disclosure and are merely
intended to describe the present disclosure, and the technical idea
of the present disclosure is not limited by those embodiments. The
scope of the present disclosure should be defined by the
accompanying claims, and the technical idea of all equivalents
thereof should be construed as being included in the scope of the
present disclosure.
* * * * *